Removal of Cr (VI) from Tannery Effluent and Aqueous Solution by Sequential Treatment with Microfungi and Basidiomycete-Degraded Sawdust

摘要

Removal of Cr (VI) from aqueous solution and tannery effluent in sequence with Cr (VI) resistant microfungi (Aspergillus niger, Penicillium chrysogenum) and sawdust degraded by basidiomycete (Gloeophyllum sepiarium) was investigated in the laboratory. Initial or primary treatment with microfungi reduced 200 mg/l Cr (VI) in aqueous solution by 64.6% - 78.2% while a markedly lower 0.52 mg/l Cr (VI) in tannery effluent was reduced by 72.4% - 84.6%. However, the residual Cr (VI) in both aqueous solution and tannery effluent was reduced to a non-detectable level after secondary treatment by passage through basidiomycete-degraded sawdust column. The recovery of 65.4% - 87.7% of the Cr (VI) removed by treatment microfungi by elution indicated adsorption as the major mechanism for Cr (VI) removal. The microfungi reduced BOD in tannery effluent by 85.3 ± 5.6 - 92.7 ± 6.8 and concomitantly removed Cr (VI), hence it is hypothesized that non-Cr (VI) constituents of tannery effluent may have interfered with biosorption of Cr (VI) by treatment microfungi. It is concluded that the two-stage sequential treatment process may be of potential cost-saving stratagem for removal of chromium from industrial wastes.